Effect of feed melting, temperature history, and minor component addition on spinel crystallization in high-level waste glass

Izak, Pavel; Hrma, Pavel R.; Arey, Bruce W.; Plaisted, Trevor J.

doi:10.1016/s0022-3093(01)00705-0

Cited by 54 publications

(44 citation statements)

References 8 publications

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“…Alton et al [3] showed that the Hixson-Crowell equation better describes spinel growth and dissolution in a HLW glass melter than the Kolmogorov-Johnson-MehlAvrami equation. Izak et al [16] presented experimental observations of spinel response to the melt temperature history and the addition of noble metals that are effective nucleation agents.…”

Section: Introductionmentioning

confidence: 99%

“…Spinel, usually a solid solution of magnetite, trevorite, nichromite and various other forms [17,18], grows and then begins to dissolve in the cold cap from which it enters molten glass [15,16]. The initial fraction and size of spinel crystals entering convection currents within the melt from the cold cap has a decisive impact on the fate of the crystals inside the melter.…”

Section: Introductionmentioning

confidence: 99%

“…This model was proven adequate for batch melting reactions [25,26] that are complete within relatively narrow intervals of temperature, allowing us to disregard the effects of their mutual interactions and use the standard nP th Porder kinetic model with constant coefficients; however, the reaction weights were functions of the heating rate. Such a simplification appears inadequate for the kinetics of quartz dissolution and spinel formation, which extend over several hundred Kelvins [2,12,16]; thus kinetic coefficients can be functions of the temperature history. We have been able to accommodate this complexity by allowing pre-exponential factors to vary with the rate of heating while keeping activation energies constant.…”

Section: Introductionmentioning

confidence: 99%

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Kinetic model for quartz and spinel dissolution during melting of high-level-waste glass batch

Pokorný

Rice

Crum

et al. 2013

Journal of Nuclear Materials

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The dissolution of quartz particles and the growth and dissolution of crystalline phases during the conversion of batch to glass potentially affects both the glass melting process and product quality.Crystals of spinel exiting the cold cap to molten glass below can be troublesome during the vitrification of iron-containing high-level wastes. To estimate the distribution of quartz and spinel fractions within the cold cap, we used kinetic models that relate fractions of these phases to temperature and heating rate. Fitting the model equations to data showed that the heating rate, apart from affecting quartz and spinel behavior directly, also affects them indirectly via concurrent processes, such as the formation and motion of bubbles. Because of these indirect effects, it was necessary to allow one kinetic parameter (the pre-exponential factor) to vary with the heating rate. The resulting kinetic equations are sufficiently simple for the detailed modeling of batch-to-glass conversion as it occurs in glass melters. The estimated fractions and sizes of quartz and spinel particles as they leave the cold cap, determined in this study, will provide the source terms needed for modeling the behavior of these solid particles within the flow of molten glass in the melter.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Kinetic model for quartz and spinel dissolution during melting of high-level-waste glass batch

Pokorný

Rice

Crum

et al. 2013

Journal of Nuclear Materials

Self Cite

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“…It was discovered early on that spinel nucleation proceeds nearly instantaneously [8]. Moreover, the feed melting studies revealed that tiny (submicron) spinel crystals precipitate already from the primary (nitrate) melt [9]. These low-chromium crystals dissolved as the conversion progressed, but could also survive as seeds for crystals that form in the glass.…”

Section: Methods and Resultsmentioning

confidence: 99%

Settling of Spinel in A High-Level Waste Glass Melter

Hrma¹,

Schill²,

Nemec³

2002

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“…Neither Tc nor Re can be directly retained in High Level Waste (HLW) glass because they volatilize before the glass is formed. However, Tc or Re-containing spinel crystals have a good chance of preserving these elements until a high temperature at which the crystals dissolve in molten glass [2].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of trevorite to capture Tc

Tsui¹

2011

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Spinel containing technetium can be used to prevent Tc volatilization during vitrification of radioactive waste. Spinel dissolves in glass at elevated temperatures. This study focuses on the synthesis of spinel and the retention of rhenium, a nonradioactive surrogate for Tc in the crystals. To produce trevorite, a nickel-iron spinel (NiFe 2 O 4 ), Fe and Ni nitrates were mixed with alkali nitrates along with Al(OH) 3 and heated to 500 to 800°C. The trevorite content in samples (up to 40 mass%) was measured with x-ray diffraction. Viable samples were rerun with KReO 4. Scanning electron microscopy-energy dispersive spectroscopy detected that Re became partly immobilized in spinel-forming crystals.v

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Effect of feed melting, temperature history, and minor component addition on spinel crystallization in high-level waste glass

Cited by 54 publications

References 8 publications

Kinetic model for quartz and spinel dissolution during melting of high-level-waste glass batch

Kinetic model for quartz and spinel dissolution during melting of high-level-waste glass batch

Settling of Spinel in A High-Level Waste Glass Melter

Synthesis of trevorite to capture Tc

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